Find active open transactions from a SQL Server Instance

SELECT
       est.session_id as [Session ID],
       est.transaction_id as [Transaction ID],
       tas.name as [Transaction Name],
       tds.database_id as [Database ID]
FROM sys.dm_tran_active_transactions tas
INNER JOIN sys.dm_tran_database_transactions tds
       ON (tas.transaction_id = tds.transaction_id )
INNER JOIN sys.dm_tran_session_transactions est
       ON (est.transaction_id=tas.transaction_id)
       WHERE est.is_user_transaction = 1 -- user
       AND tas.transaction_state = 2 -- active
       AND tds.database_transaction_begin_time IS NOT NULL
       -- Time at which the database became involved in the transaction, You can apply filter here